CN102193114A

CN102193114A - Erect equal-magnification lens array

Info

Publication number: CN102193114A
Application number: CN2010102780067A
Authority: CN
Inventors: 白石贵志
Original assignee: Toshiba Corp; Toshiba TEC Corp
Current assignee: Toshiba Corp; Toshiba TEC Corp
Priority date: 2010-03-04
Filing date: 2010-09-03
Publication date: 2011-09-21
Also published as: US20110216418A1; JP2011186429A

Abstract

There is provided an erect equal-magnification lens array including: a plurality of first lenses causing light incident from an object point to each incidence plane, which has at least a partially planar shape, to be collected by each outgoing plane which has a convex shape; a plurality of second lenses aligned so as to correspond to each of the plurality of first lenses, having incidence planes each of which has a convex shape and is arranged in the vicinity of a position in the optical axis direction, at which the light is collected by each of the outgoing planes of the plurality of first lenses, and causing the light incident to each of the incidence planes to be collected again on an image plane using outgoing planes thereof each of which has a convex shape; and an aperture configured to shield light, from among the light collected by each of the outgoing planes of the plurality of first lenses, proceeding in a direction to be incident from each of the outgoing planes to the incidence planes of the second lenses other than the second lenses on the same optical axis.

Description

Erecting equal-magnification lens array

The cross reference of related application

The application requires the right of priority of No. the 61/310636th, the U.S. Provisional Application submitted on March 4th, 2010, and its full content is hereby expressly incorporated by reference.

Technical field

The present invention relates to erecting equal-magnification lens array.

Background technology

At present, disclose erecting equal-magnification lens array with two pieces of lens arras.

These lens arras have separately in a plurality of lens combination of arranging with the direction of light shaft positive cross.

Above-mentioned existing erecting equal-magnification lens array generally makes up two pieces of identical shaped lens arras and constitutes.

Yet, under the situation of the above-mentioned existing erecting equal-magnification lens array of two pieces of formations that do not have the intermediate lens array as the erecting equal-magnification lens array that adopts three pieces of lens arras, the major part plane of incidence incident of each lens of level lens array backward before inciding in the light of each lens of level lens array exists in the few problem of the light quantity of actual imaging on the image planes.

On the other hand, disclose the countermeasure technology of in the formation that adopts two pieces of lens arras, eliminating above-mentioned deficiency in light quantity problem.

Yet, in above-mentioned countermeasure technology, form dark groove at the edge of each lens that constitutes lens arra, by this groove to the lens face direct light.Therefore, the wall thickness change of the lens arra during moulding is very big, is difficult to improve the precision of lens face shape, global shape.And, adopting as hot-forming from flat sides the material heating and push under the situation of job operation of mold, the deflection of the fluctuating of surface configuration is big, equally the existence problem that is difficult to carry out high-precision processing.

Summary of the invention

In view of the above problems, the invention provides a kind of erecting equal-magnification lens array, comprise: a plurality of first lens, be arranged on the direction with light shaft positive cross, be used for exit facet by convex surface and converge respectively from object point and incide light on each plane of incidence that at least a portion is the plane; A plurality of second lens, light going direction downstream on above-mentioned a plurality of first lens optical axis separately, be arranged in accordingly separately on the direction with light shaft positive cross with above-mentioned a plurality of first lens, and near the optical axis direction position that light each exit facet by above-mentioned a plurality of first lens converges, dispose the plane of incidence of convex surface, and converge to image planes once more respectively by the light that the exit facet of convex surface will incide the plane of incidence separately; And the perforate part, be used for blocking the light light that converges by above-mentioned a plurality of first lens exit facet separately, that advance from the direction of the plane of incidence incident of separately second lens of exit facet to above-mentioned second lens on same optical axis.

Description of drawings

Fig. 1 is the longitudinal section of formation that the scanning optics of the scanner that possesses the related erecting equal-magnification lens array Q of present embodiment is shown;

Fig. 2 is the whole concise and to the point exploded perspective view that constitutes that the related erecting equal-magnification lens array Q of present embodiment is shown;

Fig. 3 is the longitudinal section that the formation of the one group of optical elements sets of arranging along the optical axis of certain lens in the related erecting equal-magnification lens array of present embodiment is extracted expression;

Fig. 4 is the figure of relation that the formation (right figure) of the related erecting equal-magnification lens array of the function (left figure) of each lens of the erecting equal-magnification lens array that three pieces of lens of combination form and present embodiment is shown;

Fig. 5 is a planimetric map of seeing the arrangement of a plurality of first lens 101 first lens arra one from the top;

Fig. 6 is used for the intensive shape of six sides of first lens 101 and second lens 201 is disposed the figure that describes;

Fig. 7 is illustrated in the figure that direction shown in Figure 5 is arranged the appearance that light passes through under the situation in hole of first lens 101, second lens 201, the first perforate part 301 and the second perforate part 302;

Fig. 8 illustrates the figure that vertically arranges the appearance that light passes through under the situation in hole of first lens 101, second lens 201, the first perforate part 301 and the second perforate part 302 with respect to the position of Fig. 5 relation;

Fig. 9 illustrates the figure of state that cross-wise direction shown in Figure 8 is reduced the generation of parasitic light as the few direction of the arrangement columns of lens;

Figure 10 shows the first perforate part 31 that the related erecting equal-magnification lens array Q of present embodiment has been installed and the sub scanning direction cross section of the second perforate part 32;

Figure 11 illustrates the lens data synoptic diagram of the related erecting equal-magnification lens array of present embodiment;

Figure 12 illustrates the asphericity coefficient of the lens face in the related erecting equal-magnification lens array of present embodiment;

Figure 13 is the synoptic diagram of aspheric surface formula;

Figure 14 is the figure of shape of sphere portion that the exit facet 101s of first lens 101 is shown;

Figure 15 is the figure of shape of sphere portion that the plane of incidence 201f of second lens 201 is shown;

Figure 16 is the figure of shape of sphere portion that the exit facet 201s of second lens 201 is shown;

Figure 17 is used to illustrate that thereby the scattered light that does not allow from first lens, 101 peripheries arrives the figure that second lens 201 increase the condition of light quantity;

Figure 18 is the sectional view of the main scanning direction of spacing maximum between the lens of erecting equal-magnification lens array Q;

Figure 19 is the Illumination Distribution synoptic diagram on the plane of incidence 201f of second lens 201 when being illustrated under the state of Figure 18 thickness of slab with the second perforate part 32 and being made as 0.85mm;

Figure 20 is the sectional view of the sub scanning direction of spacing minimum between lens;

Figure 21 is the figure of the Illumination Distribution on the plane of incidence 201f of following thickness of slab of the second perforate part 32 of state of being illustrated in Figure 20 second lens 201 when being made as 0.85mm;

Figure 22 illustrates to have passed through the second perforate part, 32 backs on the plane of incidence 201f of second lens 201, producing the figure of the appearance of parasitic lights with all directions of light shaft positive cross;

Figure 23 is illustrated in sub scanning direction to have passed through the second perforate part, 32 backs, produced parasitic light on the plane of incidence 201f of second lens 201 and do not produce the figure of the appearance of parasitic light at main scanning direction;

Figure 24 is the figure that defocuses characteristic that the MTF (modulation transfer functions) of the six cycles/mm under the state of Figure 11 is shown;

Figure 25 is the figure that defocuses characteristic that MTF is shown;

Figure 26 is the figure that is illustrated in the state of the relation that sets when setting initial value after the optical system optimization;

Figure 27 is the table that the value on the left side in the paraxial relational expression and the right is shown;

Figure 28 is the figure of distortion that a cover lens combination of first lens 101 with Figure 11 and lens data shown in Figure 12 and second lens 201 is shown;

Figure 29 illustrates the figure that lens face is made as the distortion of the cover lens combination after being optimized under the state of sphere;

Figure 30 illustrates the figure that the lens face of first lens 101 and second lens 201 is only pressed the appearance of the light path after sphere is optimized;

Figure 31 illustrates to be made as the figure that constitutes with the same lens of the lens data of Figure 11 and the first perforate part 31 and the second perforate part 32 are combined into the formation of one piece of perforate part 3; And

Figure 32 is illustrated in writing of image processing system adopted the concise and to the point formation of erecting equal-magnification lens array Q in the optical system figure.

Embodiment

Below, with reference to accompanying drawing embodiment is described.

Fig. 1 is the longitudinal section of formation that the scanning optics of the scanner that possesses the related erecting equal-magnification lens array Q of present embodiment is shown.The related erecting equal-magnification lens array Q of present embodiment is used in the scanning optics of scanner.

Erecting equal-magnification lens array Q will utilize the light of original copy face reflection to be directed to CCD chip (light receiving element) after LED penetrates.

Certainly, also can be the constituting of reading object face that will be directed to original copy by erecting equal-magnification lens array Q from the illumination light that reads the light source in the optical system of the scanner that reads original image.

Fig. 2 is the whole concise and to the point exploded perspective view that constitutes that the related erecting equal-magnification lens array Q of present embodiment is shown.

As shown in Figure 2, the related erecting equal-magnification lens array Q of present embodiment possesses pressing plate 231, first lens arra 1, the first perforate part 31, the second perforate part 32, second lens arra 2 and pressing plate 232.

Constitute the series arrangement of above-mentioned each composed component pressing plate 231, first lens arra 1, the first perforate part 31, the second perforate part 32, second lens arra 2, the pressing plate 232 on the direct of travel of light of the related erecting equal-magnification lens array Q of present embodiment.

By connect inserting bolt, screw etc. in a plurality of hole 231h of the location usefulness that is formed with female screw and a plurality of hole 232h, first lens arra 1, the first perforate part 31, the second perforate part 32 and second lens arra 2 are fastened to each other in the mode that is clipped between pressing plate 231 and the pressing plate 232.

And, on the face of the side relative of first lens arra 1 and second lens arra 2 with the perforate part, with the face relative of the first perforate part 31, the second perforate part 32 with each lens arra on the 311s of hole portion and the pairing position of 321s of the location usefulness that forms, formed jut (for example convex lens shape) 101s and 201s.

When clamping first lens arra 1, the first perforate part 31, the second perforate part 32 and second lens arra 2 by

pressing plate

231 and 232,

clamp jut

101s and 201s on these lens arras to be embedded into 311s of hole portion on each perforate part and the state among the 321s, just can position first lens arra 1, the first perforate part 31, the second perforate part 32 and second relative position relation with direction light shaft positive cross lens arra 2.Like this, by in the location of realizing lens and perforate part with the identical shaped position of lens, thereby the moulding together when the moulding of lens arra of position that can this location is used helps lens and the raising of the relative positioning precision of locating used position and the reduction of manufacturing cost.

In addition, here, illustration form hole portion and form the formation of jut in perforate part side in the lens arra side, but be not limited thereto, also can form jut in perforate part side, form hole portion in the lens arra side.And the embedded position of jut needn't one be decided to be hole portion, also can be made as recess (for example concavees lens shape).

Fig. 3 is the longitudinal section that the formation of the one group of optical elements sets of arranging of the optical axis along certain lens in the erecting equal-magnification lens array that present embodiment is related extracts expression.Fig. 4 is the figure of relation that the formation (right figure) of the related erecting equal-magnification lens array of the function (left figure) of each lens of erecting equal-magnification lens array of three pieces of lens of combination and present embodiment is shown.Fig. 5 is a planimetric map of seeing the arrangement of a plurality of first lens 101 first lens arra 1 from the top.

First lens arra 1 has a plurality of first lens 101.It is that the exit facet 101s of light by convex surface of each plane of incidence 101f on plane converges near the plane of incidence 201f separately that a plurality of first lens 101 will incide plane or at least a portion from object point (object side).Be arranged in direction (with reference to Fig. 5) with optical axis P quadrature the intensive shape of a plurality of first lens, 101 6 sides.

Second lens arra 2 has a plurality of second lens 201.Light going direction downstream on a plurality of first lens 101 optical axis P separately, a plurality of second lens 201 and each corresponding shape of a plurality of first lens 101 are arranged in the direction with optical axis P quadrature, converge near the plane of incidence 201f of the configuration convex surface optical axis direction position of light at each the exit facet 101s by a plurality of first lens 101, the exit facet 201s by convex surface converges to image planes once more respectively with the light that incides plane of incidence 201f respectively.Therefore, a plurality of second lens 201 also be the intensive shape of six sides be arranged in direction (with reference to Fig. 5) with optical axis P quadrature.

The first perforate part 301 and the second perforate part 302 block light in the light that is converged by a plurality of first lens 101 exit facet 101s separately, that advance from the direction of the plane of incidence 201f incident of separately second lens 201 of exit facet 101s to second lens 201 on same optical axis.

Like this, the related erecting equal-magnification lens array of present embodiment is that the plane of incidence of each lens arra in the formation of three pieces of lens arras of employing and the function of such two faces of exit facet are synthesized, and respectively utilizes a face to finish respectively.In view of the above, the required lens face number of bottom line is " three faces ", can have the effect (with reference to Fig. 4) equal with the lens arra of three pieces of groups with the lens arra of two pieces of groups.

The plane of incidence 101f of first lens 101 is under the situation on plane, imaging type based on paraxial characteristic, with the distance of the plane of incidence 101f of the object point and first lens 101 is t 1, the thickness of first lens 101 is t2, the distance that first lens 101 and second lens are 201 is t3, the thickness of second lens 201 is t4, the exit facet 201s of second lens 201 is t5 to the distance of image planes, the refractive index of first lens 101 is n1, the refractive index of second lens 201 is n2, and the curvature of the exit facet 101s of first lens 101 is cv1, and the curvature of the plane of incidence 201f of second lens 201 is cv2, when the curvature of the exit facet 201s of second lens 201 is cv3, satisfy (with reference to Figure 27 described later)

(formula 1).

At this moment, cv is just (+) when the side of the light path downstream of the intersection point that is centered close to optical axis P and lens face of curvature (image planes), is when being positioned at light path upstream (object point) side negative (-).Because t1, t2, n1, t3, (n1-1) are just (+), so from following formula also as can be known, cv1 is negative (-).This expression lens face is a convex surface.

The plane of incidence 101f side of first lens 101 is made as " plane " is based on following reason.If form competent lens face at the plane of incidence, then need only to use the light of the lens that form by the lens that form at the plane of incidence with at exit facet, so just need block the part of the light of the lens effective coverage that enters into the plane of incidence, light quantity will decay as a result.On the other hand, if plane of incidence side is made as the plane, then only lean on the significant surface of the lens of exit facet side just can determine light quantity by first lens.Therefore, " zone that the light of arrival image planes passes through " among the plane of incidence 101f of first lens 101 forms the plane.

And, being the light quantity of the light that is increased in the image planes imaging, the plane of incidence 201f of second lens 201 has the ability that the exit facet 201s of near second principal point of first lens 101 (the image planes principal point is positioned at the exit facet 101s) and second lens 201 is made as conjugate relation.

Particularly, according to the imaging type of paraxial characteristic, make the plane of incidence 201f of second lens 201 have following characteristic and get final product (with reference to Figure 27 described later).

(formula 2)

In view of the above, can guide the light that penetrates from the exit facet 101s of first lens 101, make it not plane of incidence 201f side incident to the second different lens 201 of optical axis, and to the effective coverage incident of the exit facet 201s that is positioned at second lens 201 on the same optical axis.

Because t3, t4, n2, (n2-1) are just (+), so cv2 is just (+).This expression lens face is a convex surface.

Offset the idea of spherical aberration, poor, the astigmatic aberration of intelligent image, distortion aberration at the exit facet 101s of first lens 101 and the exit facet 201s of second lens 201 with same amount, contrary sign, it doubly is preferred waiting.But in fact, the plane of incidence 201f of the exit facet 101s of first lens 101 and second lens 201 can cause aberration in light path, and the image height at exit facet 201s place that causes second lens 201 is than the image height height at the exit facet 101s place of first lens 101.If the multiplying power of the exit facet 201s of the exit facet 101s of first lens 101 and second lens 201 only is made as below one times, near the situation of having blocked (ケラレ) light by this perforate part in the time of just having prevented to pass through lens that the light of the plane of incidence 201f of second lens 201 enters adjacent row at the exit facet 201s of second lens 201 and produce parasitic light or the exit facet 201s of second lens 201, be provided with the perforate part.Therefore, from guaranteeing that light quantity, parasitic light countermeasure are preferably (with reference to Figure 27 described later) the aspect

(t4/n2)/t3＜1 ... (formula 3).

The exit facet 201s of second lens 201 will converge to image planes from the light of the plane of incidence 201f side of second lens 201.Based on the imaging type of paraxial characteristic, make the exit facet 201s of second lens 201 have following characteristic and get final product (with reference to Figure 27 described later)

(formula 4).

Because t4, n2, t5, (n2-1) are just (+), so cv3 is negative (-).This expression lens face is a convex surface.

In the present embodiment, the exit facet 201s of the plane of incidence 201f of the exit facet 101s of competent first lens 101, second lens 201, second lens 201 is an aspheric surface.The aspherisation of all faces helps the improvement of MTF.

The aspherisation of the exit facet 201s of the exit facet 101s of first lens 101 and second lens 201 mainly has bigger effect aspect rectification spherical aberration, the intelligent image difference.

And the aspherisation of the plane of incidence 201f of second lens 201 produces effect for reducing the distortion aberration.

The inverse of the multiplying power that inverted image is projected into erect image in the multiplying power that is made as the inverted image in first lens arra 1 and second lens 201 is identical substantially.That is, the multiplying power of the plane of incidence 201f from object point to second lens 201 and the multiplying power from the plane of incidence 201f of second lens 201 to image planes are reciprocal relation.

Therefore, the related erecting equal-magnification lens array Q of the present embodiment expression formula that meets the following conditions, (with reference to Figure 27 described later).

(formula 5).

In the present embodiment, at the exit facet 201s of the exit facet 101s of first lens 101 and second lens 201 with contrary sign by making it to offset with volume production green-ball surface aberration, poor, the astigmatic aberration of intelligent image and distortion aberration.

Particularly, for the light that penetrates from the exit facet 101s (being equivalent to object point) of first lens 101 is accommodated in the scope of exit facet 201s of second lens 201, preferably, the multiplying power from the exit facet 101s of first lens 101 to the exit facet 201s of second lens 201 is less than 1 (for waiting doubly).Therefore, for this multiplying power is made as 1 times, by satisfying

(formula 6)

Mode constitute (with reference to Figure 27 described later).

In addition, because still residual in actual conditions aberration is arranged, so image height among the exit facet 201s of second lens 201 occurs than the high situation of image height among the exit facet 101s of first lens 101.

If this multiplying power only is made as below 1 times, the light that just can prevent to pass through the plane of incidence 201f of second lens 201 enters " parasitic light " or " the blocking of light " that this perforate part is caused under near the situation that is provided with the perforate part exit facet 201s of second lens 201 corresponding to the lens of adjacent optical axis at the exit facet 201s of second lens 201.

Therefore, from guaranteeing and the viewpoint of (2) parasitic light countermeasure of (1) light quantity, be preferably

(t4/n2)/t3＜1 ... (formula 7).

According to above-mentioned paraxial condition, set initial value, provide separating after the optimization below.

As Fig. 5 and shown in Figure 6, first lens 101 and second lens 201 with the plane of light shaft positive cross on be configured to " the intensive shape of six sides ", as shown in Figure 6, when the direction that the luminous point of line sensor or light source is arranged is called " main scanning direction ", be arranged between the lens center on the main scanning direction apart from d 1 than between lens center sub scanning direction on long apart from d2.

The lens arrangement number that this expression is arranged in distance first direction (d1 direction) farthest between the lens center of adjacency is more than the lens arrangement number that is arranged in the second direction (d2 direction) of this first direction quadrature.

If distance is big between the lens center, then can strengthen zone by the plane of incidence and the sidewall-masked parasitic light of perforate part, therefore be configured by the intensive shape configuration of six sides that can top efficiency configuration lens, and make when arranging that by the intensive shape configuration of six sides the direction far away apart from change of each lens is consistent with main scanning direction.In the present embodiment, adopt occur easily at parasitic light, the short direction (d2 direction) of distance goes up the formation that does not dispose lens in the zone that parasitic light produces between the lens center.

The effective diameter of lens be made as with the lens center between minimum value and value identical, thereby realize maximized depression (SAG) amount that suppresses simultaneously of light quantity.Fig. 7 is illustrated in the figure that direction shown in Figure 5 is arranged the appearance that light passes through under the situation in hole of first lens 101, second lens 201, the first perforate part 301 and the second perforate part 302.Fig. 8 is the figure of the appearance that light passes through under the situation in the expression hole that concerns homeotropic alignment first lens 101, second lens 201, the first perforate part 301 and the second perforate part 302 with respect to the position of Fig. 5.

If the direction of Fig. 8 is made as the few direction of arrangement columns of lens, then as shown in Figure 9, can reduces the generation of parasitic light.

In this case, sub scanning direction is for as shown in Figure 9, and main scanning direction produces parasitic light for as shown in Figure 7 so can be suppressed among the erecting equal-magnification lens array Q.

Figure 10 shows the first perforate part 31 that the related erecting equal-magnification lens array Q of present embodiment has been installed and the sub scanning direction cross section of the second perforate part 32.In the figure, the left side is object side (an original copy face), and the right side is image planes (sensor side).

The plane of incidence 201f of second lens 201 has the second principal point (principal point of image planes side that makes first lens 101, be positioned near the exit facet 101s) and the exit facet 201s of second lens 201 possess the ability of conjugate relation, can make the light exit facet 201s by second lens 201 as much as possible that has passed through first lens 101, the first perforate part 301 and the second perforate part 302.

Figure 11 shows the lens data of the related erecting equal-magnification lens array of present embodiment.Figure 12 shows the asphericity coefficient of the lens face in the related erecting equal-magnification lens array of present embodiment.

Here, the aspheric surface formula is represented (coordinate system is with reference to Fig. 3) with formula shown in Figure 13.

Be represented by dotted lines the shape of sphere portion of the exit facet 101s of first lens 101 among Figure 14, represent to comprise the shape of aspheric surface item with solid line.In Figure 14, transverse axis is represented each lens, and (point with each lens and optical axis intersection shown in Figure 3 is as the √ (x in the local coordinate system of initial point to the distance of optical axis ₂+ y ₂)), the longitudinal axis is represented height (point with each lens and optical axis intersection shown in Figure 3 is as the z in the local coordinate system of initial point).Be represented by dotted lines the shape of sphere portion of the plane of incidence 201f of second lens 201 among Figure 15, represent to comprise the shape of aspheric surface item with solid line.Be represented by dotted lines the shape of sphere portion of the exit facet 201s of second lens 201 among Figure 16, represent to comprise the shape of aspheric surface item with solid line.The aspherical shape of the condition that the shape that is represented by dotted lines of Figure 14～Figure 16 represents to suppose aspheric surface formula shown in Figure 13 during for " cc=ad=ae=af=ag=0 ".In the shape of representing with solid line that comprises the aspheric surface item of Figure 14～Figure 16, all lens faces all be along with from the lens center (optical axis P) laterally (circumference side) leave and aspherical shape that the absolute value of curvature diminishes.

Adopt under the situation of optical system of the complete symmetry that first lens and second lens wait mutually times, distortion aberration, intelligent image difference and ratio chromatism, do not produce, but, under first lens situation different with the formation of second lens, it is poor still can to produce distortion aberration and intelligent image as present embodiment.Particularly, in the related lens configuration of present embodiment, multiplying power can increase with image height, might not can converge well from the light of a plurality of lens arras.Therefore, for the generation of the deployment cost embodiment of optical element is such and inhibition distortion aberration, intelligent image difference, the exit facet 101s of first lens 101, the plane of incidence 201f of second lens 201 and the exit facet 201s of second lens 201 are made as the absolute value of curvature along with the aspheric surface that diminishes toward the outside from the lens center.

In addition, the negative quantity of the thickness of the SRF2 among Figure 11 represents that from the lens apex of the exit facet 101s of first lens 101, the first perforate part 31 is configured in the direction that is absorbed in 0.038mm towards lens.That is, as can be seen, because littler, so between the face of the lens side of the rims of the lens portion and the first perforate part 31 gapped (being equivalent to the L1 among Figure 17 described later) than amount of recess 0.08384mm.By suitably setting this gap value, can not allow the scattered light from rims of the lens arrive second lens 201, increase light quantity.

With reference to Figure 17 this condition is described.This there is shown first lens 101 and the first perforate part 31, the second perforate part 32.Light is advanced from the top down.

Concentric and radius is rap1 with the optical axis P of first lens 101 at the center of the circular hole 311a of the first perforate part 31, when the circular hole 321a of the second perforate part 32 is rap2 with respect to the highest δ of the departing from ap2 of optical axis P of first lens 101 and radius, the condition that parasitic light does not enter with first lens 101 are in the circular hole 321a of the second perforate part 32 on the identical optical axis is, having must be less than the degree of tilt L2/ (rap1+rap2+ δ ap2) of the minimum of the exiting side of the light incident side that can be by the first perforate part 31 and the second perforate part 32 from the maximum inclination L1/ (ref1-rap1) of rims of the lens by the light of the inlet of the first perforate part 31.

Therefore, must satisfy

L1/ (ref1-rap1)＜L2/ (rap1+rap2+ δ ap2) ... (formula 8)

Put this formula in order, be expressed as

L1＜(ref1-rap1)/(rap1+rap2+ δ ap2) * L2 ... (formula 9).

In following formula, the hole that is formed at the perforate part is made as circle, diameter is defined as rap1, rap2.On the other hand, the hole that is formed at the perforate part is not under the situation of circle, with the hole portion of first lens, 101 sides of the first perforate part 31 from the distance of optical axis P farthest the position and the distance of optical axis P be made as a1, with the hole portion of second lens, 102 sides of the second perforate part 32 from the distance of optical axis P position and the distance of optical axis P when being made as a2 farthest, the rap1 of (formula 9) is replaced into a1, rap2 is replaced into a2, can write

L1＜(ref1-a1)/(a1+a2+ δ ap2) * L2 ... (formula 9 ')

During δ ap2=0,

L1＜(ref1-a1)/(a1+a2) * L2 ... (formula 9 ").

Here, the perforate part is made as two pieces, but, these two pieces conditions when becoming one piece of perforate part with the form that links to each other are also identical, under this situation, as long as the hole portion radius of the lens face side of perforate part is made as rap1, the lens face side opening portion radius of perforate part is made as rap2, the core shift on perforate part two sides is made as δ ap2 just can be suitable for identical formula.

The first perforate part 31 and the second perforate part 32 are independent at optical axis direction, and separate configuration, according to consideration same as described above, can prevent that the conditional expression that the light that penetrates from the exit facet 101s along first lens 101 of certain optical axis P enters as parasitic light the circular hole 321a of the second perforate part of arranging along the optical axis P ' (with reference to Figure 17) different with the optical axis of these first lens 32 from being

(L1+L2)/(a4+ref1)＞(L1+L2-L3)/(a3+ref1) ... (formula 10).

The inradius of the effective portion of lens of first lens 101 (in the lens outer peripheral face from the distance of optical axis minimum diameter or the effective portion of lens radius) is made as ref1 here.

The distance at optical axis direction with first lens, 101 immediate edge parts from the lens outer peripheral edges portion of first lens 101 to the 311a of hole portion of the first perforate part 31 is made as L1.

The distance at optical axis direction from the face of first lens, 101 sides of the first perforate part to the face of second lens, 201 sides of the second perforate part 32 is made as L2.

The thickness at optical axis direction of the second perforate part 32 is made as L3.

To be made as a3 to the bee-line that is formed on the inner peripheral surface of the 321a of hole portion the second perforate part 32 accordingly with another first lens 101 that are adjacent to these first lens 101 from the optical axis of first lens 101.

To be made as a4 to the longest distance that is formed on the inner peripheral surface of the hole portion the second perforate part 32 accordingly with another first lens 101 that are adjacent to these first lens 101 from the optical axis of first lens 101.Formula 10 can be rewritten as follows.

L3＞(a4-a3)/(a4+ref1) * (L1+L2) ... (formula 11)

In addition, light going direction downstream on the optical axis of each above-mentioned a plurality of first lens, a plurality of second lens and each above-mentioned a plurality of first lens are arranged in the direction with light shaft positive cross accordingly, converge near the optical axis direction position of light configuration at each exit facet as the plane of incidence of convex surface by above-mentioned a plurality of first lens, such formation, in other words, the plane of incidence 201f that means the object point and second lens 201 possesses conjugate relation.

And, with incident separately light converge to image planes once more respectively by exit facet 201s as convex surface, in other words, such formation means that the plane of incidence 201f and the image planes of second lens 201 possess conjugate relation.

Below, with reference to formula 11, offset except that the thickness L3 of the second perforate part 32 of parasitic light according to the direction of the intensive shape configuration of lens six sides and different situations describes.

Will the member that has formed the hole on the thin sheet material be piled up under the situation of making the perforate part or by repeatedly repeatedly printing make under the situation of perforate part, during the thin thickness of perforate part since overlapping number of times reduce, so can reduce cost., be made as δ ap2=0 here, the aperture of the 321a of hole portion of the second perforate part 32 is all rap2 in plane of incidence side and exit facet side.

At first, lens and perforate part are regarded as at main scanning direction and sub scanning direction be infinity.

Figure 18 shows the sectional view of the main scanning direction of spacing maximum between the lens of erecting equal-magnification lens array Q.Figure 19 shows the Illumination Distribution on the plane of incidence 201f of second lens 201 when following thickness of slab of the second perforate part 32 of Figure 18 state is made as 0.85mm.At this moment, if lenticular spacing from bee-line be made as p, then between the lens center of main scanning direction apart from being √ 3 * p, therefore

A3=√ 3 * p-rap2, a4=√ 3 * p+rap2 ... (formula 12).

Wushu 12 substitution formulas 11, then

L3＞(2 * rap2)/(√ 3 * p+rap2+ref1) * (L1+L2) ... (formula 13)

That is, under the situation of lens data shown in Figure 11, become L3＞0.548.

Figure 20 represents the sectional view of the sub scanning direction of spacing minimum between lens.Illumination Distribution on the plane of incidence 201f of second lens 201 when Figure 21 is illustrated in following thickness of slab of the second perforate part 32 of state shown in Figure 20 and is made as 0.85mm.

At this moment, if lenticular spacing from bee-line be made as p, then between the lens center of sub scanning direction apart from being √ 3 * p, therefore, become a3=√ 3 * p-rap2, a4=√ 3 * p+rap2.

With its substitution formula 11, then

L3＞(2 * rap2)/(√ 3 * p+rap2+ref1) * (L1+L2) ... (formula 14)

Under the situation of lens data shown in Figure 11, become L3＞0.754.Be made as L3=0.85mm here.

Above-mentioned situation is the condition that enters adjacent lenses from the parasitic light of rims of the lens, and but, if satisfy formula 13,14 at the lens face Zone Full, then the light that satisfies by first lens face does not enter the such condition of adjacent lenses.This is equivalent to forward the ref1 of formula 13, formula 14 to ref1 from-ref1.

The situation that the right of formula 13, formula 14 becomes maximum is ref1 to be made as-during ref1, to press

L3＞(2 * rap2)/(√ 3 * p+rap2-ref1) * (L 1+L2) ... (formula 15)

L3＞(2 * rap2)/(p+rap2-ref1) * (L1+L2) ... (formula 16)

Under the situation of lens data shown in Figure 11, in formula 15 L3＞0.927, in formula 16 L3＞1.635.

That is, L3＞1.635 o'clock, no matter the value of L4 is how, with all directions of light shaft positive cross on, light does not enter the adjacent lenses array.1.635＞L3＞0.927 o'clock, no matter the value of L4 how, in the direction of spacing maximum, light does not enter the adjacent lenses array, and but, in the direction of spacing minimum, with the difference of the value of L4, light can enter the adjacent lenses array, becomes parasitic light.

L3＜0.927 o'clock, the difference with the value of L4 all has the possibility that produces parasitic light in all directions with light shaft positive cross.As mentioned above, in Figure 11, be made as L3=0.85, so, all can produce parasitic light in all directions with light shaft positive cross with the difference of the value of L4.

Figure 22 illustrates to have passed through after the second perforate part 32 on the plane of incidence 201f of second lens 201, producing the figure of the appearance of parasitic light with all directions of light shaft positive cross.(L3=0.5mm is during L4=0.1mm.As can be seen, also produced parasitic light a little at above-below direction (main scanning direction).)

It is as follows to only depend on the second perforate part 32 can not cut off the condition that the light shown in Figure 17 1 under the situation of parasitic light blocked by the exiting side of the first perforate part 31:

A3-(a4-a3)/L3 * (L2-L3-L4)＞a1 ... (formula 17)

Here, L4 is the thickness of the first perforate part 31 at optical axis direction.Thickness L4 to the first perforate part 31 summarizes, then

L4＞(a1-a4)/(a4-a3) * L3+L2 ... (formula 18)

The direction of spacing maximum is made as a1=rap1 between lens, then

L4＞(rap1-√ 3 * p-rap2)/(√ 3 * p+rap2-√ 3 * p+rap2) * L3+L2 ... (formula 19)

It is summarized, then

L4＞(rap1-√ 3 * p-rap2)/(2 * rap2) * L3+L2 ... (formula 20)

The direction of spacing minimum is made as a1=rap1 between lens, then

L4＞(rap1-p-rap2)/(p+rap2-p+rap2) * L3+L2 ... (formula 21)

It is summarized, then

L4＞(rap1-p-rap2)/(2 * rap2) * L3+L2 ... (formula 22),

The right of formula 20 is littler than the right of formula 22, therefore,

L4＞(rap1-p-rap2)/(during 2 * rap2) * L3+L2, can not produce parasitic light in omnirange, when

(rap1-p-rap2)/(2 * rap2) * L3+L2＞L4＞(rap1-√ 3 * p-rap2)/(2 * rap2) * L3+L2 ... when (formula 23),

In the direction of spacing maximum, light can not enter the adjacent lenses array, and but, in the direction of spacing minimum, light can enter the adjacent lenses array, becomes parasitic light.

, in fact make for a short time because of lens width here at sub scanning direction, so if can take parasitic light to the zone that does not have the hole of lens, perforate part, even

(rap1-p-rap2)/(2 * rap2) * L3+L2＞L4＞(rap1-√ 3 * p-rap2)/(2 * rap2) * L3+L2 ... (formula 23)

State, can prevent that also parasitic light from reaching image planes.

As the condition that realizes this point, must make be easy to generate most parasitic light, the direction of spacing minimum is consistent with sub scanning direction between lens, and is and satisfied

L4＞(rap1-√ 3 * p-rap2)/(2 * rap2) * L3+L2 ... (formula 20).

Lens data is as shown in figure 11 the time, L3=0.85mm, and the right of formula 20 is for-0.042130833 (if expression thickness is more than 0 then does not produce parasitic light at main scanning direction.), the right of formula 22 is 0.636679916.Because L4=0.5mm so at sub scanning direction, passed through after the second perforate part 32, can produce parasitic light on the plane of incidence 201f of second lens 201, then do not produce parasitic light here, at main scanning direction.Figure 23 represents its appearance.Figure 23 only shows parasitic light to block the state of original light.In Figure 23, above-below direction is a main scanning direction, and left and right directions is a sub scanning direction.As can be seen from Figure 23,, make its position range avoid producing the position of parasitic light, just be not subjected to the influence of parasitic light if the lens of sub scanning direction are located at the inboard.The scope of dotted line shown in Figure 23 is the example of lens range that is not subjected to the influence of parasitic light.

And, find studied the combination in all thickness, aperture for the various first perforate parts 31 and the second perforate part 32 after, be made as under the situation thicker at thickness, have the tendency of the thickness sum of two pieces of perforate parts of energy attenuate than the thickness of the first perforate part 31 with the second perforate part 32.

Therefore, in the present embodiment, the thickness that is made as the second perforate part 32 is thicker than the thickness of the first perforate part 31.In view of the above, can cost control under minimum situation, cut off the parasitic light that comes out around the lens of the exit facet 101s of first lens 101.

Under the situation of lens data shown in Figure 11, during δ ap2=0, become L 1＜0.056, L3＞0.753.Figure 24 is the figure that defocuses characteristic of MTF of the six cycles/mm under the state of expression Figure 11.

The optical efficiency of the lens face of this moment is 2.242%.As can be seen, during L1=0mm, promptly, optical efficiency when making the edge contact of first lens 101 of the first perforate part 31 and first lens arra 1 as before is 2.116%, by making the perforate part separate (being made as L1=0.056mm), increased about 6% light quantity from the edge of first lens 101 of first lens arra 1.

Even make the state of edge contact of first lens 101 of the first perforate part 31 and first lens arra 1, if the internal diameter of the circular hole 311a of the first perforate part 31 is expanded to rims of the lens, also can improve light quantity, but, the circular hole 311a core shift of first lens 101 and the first perforate part 31 time, the light that has passed through the lens significant surfaces can produce the parasitic light of big light quantity.By contrast, under the situation that lens arra and perforate part are separated, even the circular hole 311a core shift of first lens 101 and the first perforate part 31 time, also just inciding the light quantity of second lens 201 of adjacency of back level and the whole parasitic light that produces from the part of the scattered light of first lens, 101 peripheries can be littler.

And when making the perforate part, under the situation with formation circular holes such as drifts, if circular hole is excessive, then perforate part global shape might be crooked.Therefore, do not add the variation that the related formation of present embodiment that the large aperture just can obtain light quantity also helps the manufacture method selection scheme.

In lens data shown in Figure 11, the distance between centers at sub scanning direction of the 321a of hole portion of the second perforate part 32 is made as under the situation of 0.66mm, can use lens from the middle position to the secondary series at sub scanning direction, therefore maximum core shift is (0.66-0.6) * 2=0.12.That is, maximum core shift amount is δ ap2=0.12, at this moment, becomes L1＜0.046, L3＞0.753.

Under this situation, make light quantity recruitment that the spacing at sub scanning direction at center of the circular hole 321a of the second perforate part 32 causes greater than other spacings with identical substantially by increasing the light quantity reduction amount that δ ap2 diminishes L1 to cause, optical efficiency is 2.242%.

Here, make the second perforate part 32 circular hole 321a the center in the spacing of sub scanning direction greater than other spacings, mean the position of being centered close to of each circular hole beyond the circular hole of the middle position that is in sub scanning direction in a plurality of circular holes than the more close sub scanning direction outside, center of first lens 101 of correspondence.

In lens data shown in Figure 11, the aperture of the 321a of hole portion of the second perforate part 32 is made as 0.15mm, this situation is studied.

It is identical that first lens arra 1 and second lens arra 2 and the spacing of the 311a of hole portion of the first perforate part 31 are made as, the shortest 0.6mm that is spaced apart.

As mentioned above, spacing is under the situation of 0.6mm between the hole of all parts, becomes L1＜0.071, L3＞0.459928286.Figure 25 represent under this situation MTF defocus characteristic.The optical efficiency of this moment is 0.724%.

And, the spacing of the 321a of hole portion of the second perforate part 32 is made as 0.6mm at main scanning direction, be made as at sub scanning direction under the situation of 0.66mm, optical efficiency is 1.091%, can increase about 50%.Figure 26 represent at this moment MTF defocus characteristic.

Same degree substantially when the depth of focus of sub scanning direction can be decreased to aperture with the 321a of hole portion of the second perforate part 32 and is 0.55mm, but, because the aperture is little, it is big that the width of the wall between circular hole and the circular hole becomes, compare when big, can suppress the generation of the parasitic light that core shift caused of lens and perforate part significantly with perforate part diameter.

Figure 27 is after being illustrated in optical system optimization, the figure of the state of the paraxial relation that sets when setting initial value.Initial value is that the right and the left side equate, but the value on the right and the left side also occurs 25% degree difference, but, is essentially the value near relational expression.

Below the exit facet 201s that means the exit facet 101s that makes first lens 101 and second lens 201 possessed conjugate relation so that improve the following formula of light quantity

Investigate.

,, be preferably and wait times by with amount, produce spherical aberration, poor, the astigmatic aberration of intelligent image and distortion aberration and make it to offset at the exit facet 201s of the exit facet 101s of first lens 101 and second lens 201 from such idea with contrary sign.But in fact, the plane of incidence 201f of the exit facet 101s of first lens 101 and second lens 201 can cause aberration in light path, cause the image height phenomenon higher than the image height among the exit facet 101s of first lens 101 among the exit facet 201s of second lens 201 to occur.If the multiplying power of the exit facet 201s of the exit facet 101s of first lens 101 and second lens 201 only is made as (being 0.91 in the present embodiment) below 1 times, just can prevent to pass through the generation that the light of the plane of incidence 201f of second lens 201 enters the parasitic light of the lens of arranging along adjacent optical axis at the exit facet 201s of second lens 201, near the phenomenon that is shut out the light by this perforate part when perhaps being provided with the perforate part exit facet 201s of second lens 201 produces.

Therefore, from guaranteeing that the viewpoint that light quantity, inhibition parasitic light produce preferably is made as

(t4/n2)/t3＜1。

As descending most shown in the hurdle of Figure 27, the left side of following formula is 0.912206, less than 1.

Figure 28 is the figure of distortion that a cover lens combination of first lens 101 with Figure 11 and lens data shown in Figure 12 and second lens 201 is shown.Figure 29 illustrates the figure that lens face is made as the distortion of the cover lens combination after being optimized under the state of sphere.

As shown in figure 28, as can be seen,, compare, improved distortion with situation shown in Figure 29 by the lens face aspherisation.

Figure 30 is the figure that the light path after the lens face of first lens 101 and second lens 201 only is optimized with dome shape is shown.As can be seen, because distortion is just (+) and very big, on image planes, understand in different local imagings so passed through the light of each lens combination.

In addition, in the above-described embodiment, illustration the perforate part by the first perforate part 31 and the second perforate part, 32 these two situations about constituting, but be not limited thereto.For example, also can realize the function of the first perforate part 31 and the second perforate part 32 with one piece of perforate part.

Figure 31 illustrates to be made as with the same lens of the lens data of Figure 11 the figure that constitutes, the first perforate part 31 and the second perforate part 32 are combined into the formation of one piece of perforate part 3.

Like this,, in the erecting equal-magnification lens array that constitutes by two pieces of lens and perforate part, do not reducing light quantity significantly, do not adding under the situation of ladder of deep opening spare, also can suppress the generation of parasitic light, can realize good MTF according to present embodiment.

As described in detail above, according to the technology of putting down in writing in this instructions, can provide light quantity more erecting equal-magnification lens array with the formation of two pieces of lens.

In addition, in the above-described embodiment, illustration in the optical system of scanner, adopted the situation of erecting equal-magnification lens array Q, but be not limited thereto, for example, shown in figure 32, can certainly be at the erecting equal-magnification lens array Q that adopts above-mentioned embodiment in the optical system that writes of image processing system.

Under this situation, erecting equal-magnification lens array Q will be from the light-sensitive surface that is directed to photoreceptor to the photoreceptor irradiation from the light that writes the light source in the optical system of the light of LED, EL illuminating part.At this moment, " first direction " is equivalent to main scanning direction.

Though be illustrated with regard to certain embodiment, these embodiments are just given an example, and are not used in to limit the scope of the invention.In fact new method and system described herein can embody with other variety of ways, and in addition, the various omissions of method and system described herein, replacement and change all belong in the scope of aim of the present invention.Claims and equivalent thereof are intended to contain all any way and modifications of conforming to aim with the scope of the invention.

Claims

1. erecting equal-magnification lens array comprises:

A plurality of first lens are arranged on the direction with light shaft positive cross, are used for exit facet by convex surface and converge respectively from object point and incide light on each plane of incidence that at least a portion is the plane;

A plurality of second lens, light going direction downstream on described a plurality of first lens optical axis separately, be arranged in accordingly separately on the direction with light shaft positive cross with described a plurality of first lens, and near the optical axis direction position that light each exit facet by described a plurality of first lens converges, dispose the plane of incidence of convex surface, and converge to image planes once more respectively by the light that the exit facet of convex surface will incide the plane of incidence separately; And

The perforate part is used for blocking the light light that converges by described a plurality of first lens exit facet separately, that advance from the direction of the plane of incidence incident of separately second lens of exit facet to described second lens on same optical axis.

2. erecting equal-magnification lens array according to claim 1, wherein,

The curvature of the plane of incidence of described second lens is greater than the curvature of the exit facet of described first lens.

3. erecting equal-magnification lens array according to claim 1, wherein,

The zone that light passed through in the plane of incidence of described first lens, that arrive described image planes forms the plane.

4. erecting equal-magnification lens array according to claim 1, wherein,

The plane of incidence of described object point and described second lens is conjugation,

The plane of incidence of described second lens and image planes are conjugation.

5. erecting equal-magnification lens array according to claim 1, wherein,

Number at described first lens of arranging on the main scanning direction and described second lens is more than the number of described first lens of arranging on sub scanning direction and described second lens,

Described perforate part comprises and the corresponding a plurality of perforate parts of light that penetrate from the exit facet of described a plurality of first lens,

Each the perforate part except the perforate part of the middle position that is in described sub scanning direction in described a plurality of perforate part be centered close to the position that more relies on the sub scanning direction outside than the center of described first lens of correspondence.

6. erecting equal-magnification lens array according to claim 1, wherein,

The exit facet that the plane of incidence of described second lens has the exit facet that makes described first lens and described second lens possesses the ability of conjugate relation.

7. erecting equal-magnification lens array according to claim 1, wherein,

The multiplying power of the plane of incidence from object point to described second lens is a reciprocal relation with multiplying power from the plane of incidence of described second lens to image planes.

8. erecting equal-magnification lens array according to claim 1, wherein,

Multiplying power from the exit facet of described first lens to the exit facet of described second lens is less than 1.

9. erecting equal-magnification lens array according to claim 1, wherein,

The plane of incidence of described second lens be curvature absolute value along with from the lens center toward the outside and the aspheric surface that diminishes.

10. erecting equal-magnification lens array according to claim 1, wherein,

Described perforate part comprises the first perforate part and is positioned at the light going direction upstream side of the described first perforate part and the second perforate part thicker than the described first perforate part.

11. erecting equal-magnification lens array according to claim 10, wherein,

The inradius of the effective portion of lens of described first lens is made as ref1,

The distance at described optical axis direction with the immediate edge part of described first lens from the lens outer peripheral edges portion of described first lens to the hole portion of the described first perforate part is made as L1,

The distance at described optical axis direction from the face of the described first lens side of the described first perforate part to the face of the described second lens side of the described second perforate part is made as L2,

The thickness at described optical axis direction of the described second perforate part is made as L3,

To be made as a3 to the bee-line that is formed on the inner peripheral surface of the hole portion on the described second perforate part accordingly with another first lens that are adjacent to these first lens from the optical axis of described first lens,

To from the optical axis of described first lens when the longest distance that is formed on the inner peripheral surface of the hole portion on the described second perforate part accordingly with another first lens that are adjacent to these first lens is made as a4, satisfy

L3＞(a4-a3)/(a4+ref1)×(L1+L2)。

12. erecting equal-magnification lens array according to claim 10, wherein,

To be made as a1 to the longest distance that is formed on the inner peripheral surface of the hole portion on the described first perforate part accordingly with these first lens from the optical axis of described first lens,

Will be when the longest distance that is formed on the inner peripheral surface of the hole portion on the described second perforate part accordingly with these first lens be made as a2 from the optical axis of described first lens, satisfy L1＜(ref1-a1)/(a1+a2) * L2.

13. erecting equal-magnification lens array according to claim 12, wherein,

L3＞(a4-a3)/(a4+ref1)×(L1+L2)。

14. erecting equal-magnification lens array according to claim 1, wherein,

Described first lens and described second lens with the plane of light shaft positive cross on be arranged in the intensive shape of six sides, and the lens arrangement number of distance between centers first direction farthest of lens that is arranged in adjacency is than many with the lens arrangement number of the second direction of this first direction quadrature.

15. erecting equal-magnification lens array according to claim 14, wherein,

Described erecting equal-magnification lens array be read original copy image read in the optical system, will be directed to the lens arra of the reading object face of original copy from the light of light source,

Described first direction is a main scanning direction.

16. erecting equal-magnification lens array according to claim 14, wherein,

Described erecting equal-magnification lens array be read original copy image read in the optical system, will be directed to the lens arra of light receiving element from the reflected light of original copy,

Described first direction is a main scanning direction.

17. erecting equal-magnification lens array according to claim 14, wherein,

Described erecting equal-magnification lens array be to the photoreceptor irradiates light write in the optical system, will be directed to the lens arra of the light-sensitive surface of photoreceptor from the light of light source,

Described first direction is a main scanning direction.